Expansion shield



July 26, 1927.

c. c. TOMKINSON EXPANSION snnaw Filed Dec. 20. 1922 ATTORNEY Patented July 26, 1927.

UNlTED STATES PATENT QFFICE.

CHARLES C. .TOMIIKINSON, '0! 'PLAINFIELD, NEW JERSEY, AfiSIGNOR '20 J. EDWARD OGDEN, 01' KOU'NTAIHVILBE, NEW YORK.

EXPANSION snrntn.

A lication ma December 20,1922. Serial 110. 602,366.

This invention relates to expansion shields employed for obtaining anchorage in walls of brick or stone or cementitious material not adapted to directly receive a threaded P element or bolt.

This invention has for its object to provide a shield having superior gripping qualities and a shield that will gradually increase its gripping effect as the expanding element advances therein. 7

Another object of the invention is to provide a shield of the character described that is simple in construction and can be economi cally manufactured.

Further objects of the invention will appear from the following specification taken in connection with the drawings, which form a part of this application, and which Fig. 1 is an elevational view of an expansion shield constructed in accordance with the invention.

2 is an elevational view taken at right angles to Fig. 1.

Fig. 3 is a transverse sectional elevation taken substantially on line 33 of Fig. 1.-

Fig. 4 is an elevational view of the inner end of the shield shown in Fig. 2.

Fig. 5 is a transverse sectional elevation taken substantially on line 5-5 of Fig. 4.

Fig. 6 is a sectional elevation similar to Fig. 5 but showing the shield partially expanded in a wall opening.

Fig. 7 is an elevational view of the shield showing the excess metal before it is folded back on the outer surface of the shield.

Fig. 8 is a detail elevational view showing a strip ofexcess metal used in connection with the shield shown in Figs. 1 to 6 and preferably welded thereon.

Fig. 9 is an elevational view similar to Fig. 1 but illustrating another form of the invention Fig. 10 is an elevational view taken at right angles to Fig. 9.

Fig. 11 is an elevational view of the inner end of the shield shown in Figs. 9 and 1-0.

Fig. 12 is a view half in section and half in elevation illustrating another form of the invention, and

Fig. 13 is a sectional elevation illustrating a still further form of the invention.

The invention briefly described consists of an expansion shield having superimposed on its outer surface and connected thereto excess metal tapered in width longitudinally of the shield and having its greatest cross Y sectional dimension at the inner end of the shield, this dimension'gradually decreasing toward the outer end of the shield. This excess metal may he formed integral with the shield or may be secured thereto in any suitable manner by welding and, if desired, .a plurality of excess metal layers maybe used. As the expanding element advances into the shield. from the outer toward the inner end thereof, the excess metal is torced outwardly into engagement with the bore of the opening, and from the proportions of thesuper'imposed metal it will be evident that a small area will he initially forced outwardly and that this area will increase as the expanding element advances. Further details of theinvent'ion will be clear from the following description.

lhe expansion shield may be of any desired shape or form and in the embodiment oithe invention shown the shield comprises a pair of sections 20 and 21, one of the sections having tabs 22 engaging the other section and retaining the sections together. a The two sections are tapered lon itudi- Dally nsshown particularly in Fig. 2 to form a constricted bore decreasing in width from the outer to the inner end of theshie'ld on an axis at right angles to the line of division between the sections. The two sections are corrugated longitudinally, the corrugations registering to form a screw thread for receiving alag screw 23,

Each section has superimposed on the tapered portion of its outer surface and intermediate the longitudinal edges thereof ex .cess metal and in the form of the invention shown in F 1 to 7 inclusive this excess metal is formed by a substantially triangular extensionQl of theshield material, this por tion 24 extending beyond the inner end of the shield. The extension 24 is bent back wardly onto the outer surface of the shield as shown in Figs. 1,. 2, 5 and 6 with the apex of the triangle extending toward the outer end of The excess metal extension'or strip 2a is transversely corrugated in amanner similar to the shieldsections welding. The piece 26 is also preferably triangular with the apex extending toward the outer end of the shield.

From the showing in Figs. 1, 2 and 5 it will be noted that the outer portions of, the shield and excess metal lie in substantially a single cylindrical surface.

In the form of the invention shown in Figs. 9 and 10, the excess metal strip 30 is also tapered in width, being substantially triangular in outline but is also corrugated longitudinally as shown at 31 in Fig. 11. The outer end of the shield illustrated in Figs. 9 and 10 is flared at 32 to increase the diameter of this end a sufficient extent to cause the outer periphery ofthe outer end of the shield to lie in a cylinder including in its surface also the outer surfaces of the corrugations 31 of the excess metal 30. In the form of the invention shown in Figs. 9 and 10, the excess metal 30 may be secured to the shield in an desired manner.

A modification o' the construction shown in Figs. 9 to 11 is illustrated in Fig. 12 and in this form of the invention the excess metal 40 is formed from separate material and is secured to the shield by means of tabs 41 which are bent around the edges of the shield sections. The shield sections are bent back at their ends providing end portions 42 which close the inner ends of the corrugations, thereby preventing cement or wall material from entering the corrugations of the strip 40,

In Fig. 13 the excess metal 50 is made thicker at its apex than the remaining portions thereof and, therefore, as this shield is inserted in the opening, it must be driven therein by force and Withdrawal thereof from the opening is prevented by the wedging action of the end of the excess metal 50.

In use the shields shown in Figs. 1 to 12 inclusive are inserted in a wall opening and expanding means such as a lag screw is inserted in the shield. As this screw advances in the shield more and more excess'metal will be forced into engagement with the bore of the opening, the engaging area increasing gradually, thereby also increasing the gripping effect of the shield. This action is also true of the construction shown in Fig. -13 but as above stated the shield illustrated in Fig. 13 must be initially forced into the opening unless the opening is of sufficient dimension to receive the outwardly extending end portions of the excess metal 50.

Although certain specific embodiments of the invention have been shown and described, it will be understood that the invention is capable of modification and that further changes in the construction and in the arrangement of the various cooperating parts may be made without departing from the spirit or scope of the invention as expressed in the following claims.

What I claim is:

1. An expansion shield comprising a pair of expansible I sections forming a tubular member constricted to form a bore varying from a circle to an oval in cross section from end to end, the shorter axis of the oval being disposed substantially atright angles to the plane of division of the shield sections, and excess metal secured to the outer surfaces of said sections intermediate and spaced from the longitudinal edges thereof.

2. An expansion shield comprising a pair of expansible sections forming a tubular member constricted to form a bore varying from a circle to an oval in cross section from end to end, the shorter axis of the oval being disposed substantially at right angles to the plane of division of the shield secti0ns,and excess metal secured to the outer surfaces of said sections intermediate and spaced from the longitudinal edges thereof, said excess metal increasing in cross sectional dimension from the outer to the inner end of the shield.

23. An expansion shield comprising a pair of expansible sections forming a tubular member constricted to form a bore varying from a circle to an oval in cross section from end to end, the shorter axis of the oval being disposed substantially at right angles to the plane of division of the shield sections, and excess metal secured to the outer surfaces of said sections intermediate and spaced from the longitudinal edges thereof. said excess metal increasing in cross sectional dimension from the outer to the inner end of the shield and having its greatest cross sectional dimension at the most constricted portion of the shield.

4. An expansion shield comprising a pair of sections. each section having secured to its outer surface intermediate and spaced from the longitudinal edges thereof a plurality of layers of excess metal.

An expansion shield comprising a pair of sections, each section having secured to its outer surface, intermediate and spaced from the longitudinal edges thereof, a plurality of layers of excess metal, said layers decreasing in width from the inner toward the outer end of the shield.

6. An expansion shield comprising a pair of sections, each section having secured to its outer surface, intermediate the longitudinal edges thereof, a plurality of layers of excess metal, certain of said layers being formed integral with the sections and others welded thereto. a

In witness whereof, I have hereunto set my hand this 16th day of December, 1922. CHARLES C. TOMKINSON. 

